Most efficient way to use a/c???

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vitauta

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with this this oppressively hot and extensive heat wave, i've had to run my a/c much more than usual. i've asked around about what is the most economical way to run the a/c, continuously or off-and-on. nobody seems to know for sure, but lots of conflicting opinions. i have been trying to limit my central a/c use by turning it on only for short periods, with auxiliary use of a fan. but i worry that i may be actually defeating my purpose (saving money) with the unit turning on and off as i have been using it. does anyone have reliable information on this topic, or a link? what an obscene summer!!!!:ohmy:
 
I recommend setting the temperature and letting the AC work to maintain that temperature. It's really no different from heating your home in the winter.

If you have a two story home with bedrooms in the upper level, you may find the top floor is always hotter. Close the vents on the lower floor where the thermostat is and open the vents on the second floor rooms so it will cool more evenly. Also, you can leave the fan running all the time to even out the temperatures on different levels.

If you use a floor or table fan to circulate air in the room you're in, you can be comfortably cool at a higher temperature. Running a fan is a LOT less costly than running AC.
 
All summers are obscene here....We set them on 75* and let er rip! ~~ Some days they run a lot... other days (rainy) not so much. It balances out. YMMV
 
I agree with both of the above. Set it and leave it alone. Using fans (especially ceiling fans) can help distribute the air and may help make the a/c work more efficiently.
 
Good advice above. We just set it for 75 during the day and 72 at night. I let the thermostat do the work. And if it gets too hot upstairs I go to the basement and sleep on the couch. It's comfortable and cool down there.

Another thing that helps is to draw all the blinds during the day, so the sun isn't beating in through the windows. That one thing seems to make a huge difference in our house.
 
with this this oppressively hot and extensive heat wave, i've had to run my a/c much more than usual. i've asked around about what is the most economical way to run the a/c, continuously or off-and-on. nobody seems to know for sure, but lots of conflicting opinions. i have been trying to limit my central a/c use by turning it on only for short periods, with auxiliary use of a fan. but i worry that i may be actually defeating my purpose (saving money) with the unit turning on and off as i have been using it. does anyone have reliable information on this topic, or a link? what an obscene summer!!!!:ohmy:

I think it would depend on your particular a/c. Mine doesn't have a thermostat you can set, just a dial for low to high cooling.

Even on the lowest setting, it will run for 6 minutes, then off for only 3 minutes.

I finally settled on running it at a colder setting for as many minutes as it takes to get the edge off, then turning it off for as long as I feel comfortable. My electric bill hasn't been very high at all.
 
We have 2 air conditioning systems :)

One is throughout the whole house, it is evaporative, where you have to leave some windows open slightly. This one uses water. This one is by far the most cost efficient one.

The other one is a split reverse system on the wall...it is refrigerated and also is a heater...that one ends up costing more since it is all electricity

We tend to use the wall air con on the humid days as evaporative is hopeless on those muggy days, but it is perfect for dry heat
 
The original post mentions central air which, from everything I have heard (and through personal experience) works best if set at a certain temperature and left on. When you find a setting that works well for you, you will stay cool without having to freeze and boil alternately. :cool:
 
I set my AC for the warmest temperature I am comfortable with and leave it there. I also set the fan to stay on rather than cycle with the refrigeration or otherwise the air gets stuffy and clammy.

If the air gets comfortable outside at night, switch to fans as soon as outside air feels sufficiently comfortable. Depending on floor plan and room occupancy it may help to close up the house except for two windows (across the house to provide cross ventilation) and set a fan in one window. I like to have an exhaust fan in a room other than bedroom, then leave BR window open to get outside cool air without noise of fan.

Close up the house in the morning as soon as outside temperature equals inside temperature. I can usually get a few/several hours of fan-only comfort before the temperature becomes uncomfortable and I have to turn on AC.

Wear light clothing if it will help you feel comfortable at a higher temperature. If that's no clothing then close the front blinds! :)
 
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I have central air & heat, but wondered if these portable a/c work - just to cool down one room. I've seen them advertised on the shopping channels.

EdgeStar Extreme Cool 12,000 BTU Portable Air Conditioner with Silver Ion Filter - AP12001S#

If I remember, the last place had a digital timer, so you don't have to run it when you're not at home, or have it shut off or turn on at a certain time.

Probably can't hurt to clean the vents, ducts & change or clean the filters regularly.

AC Duct Cleaning | eHow.com
 
I have one of those portable room a/c units at the farm. You do need to empty them almost every 24 hours. Fortunately, the unit shuts off when the tank is full.

Because of TOU electricity rates, the central A/C gets turned on only during the lowest rate times--7 p.m. to 7 a.m. Running the A/C during the most expensive rate period would up the cost of running it by 66%. I try to turn it on only when the house is 28C (~82F) or warmer. During the day, the windows are closed and covered. I try to restrict the amount of cooking and the number of times the dogs go in and out, and out and in. Fortunately, we have had nighttime temperatures of about 50-52F for the past couple of nights, so windows open at night, closed during the day. It promises to heat up again tomorrow through Sunday...and with that, the humidity arrives and the nighttime temps won't be as cool.

I so hate TOU electricity rates.
 
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There are a lot of variables. I live in a townhouse and it is much easier to cool than a freestanding house. With our old system (27 years old) we would have to set one temperature and let it stay at that for 24 hours, trying to recover even just 5 degrees took hours of it running constantly. The new system, we have it set for 80 degrees when we are not here, 74 in the evening, and 71 at night, and it cycles on and off. It is a much better system, that is a little larger (the house has more finished square footage that it did when it was built), and recovers quickly.

Luckily electric rates in my state aren't terrible, so it isn't extremely costly to stay comfortable.
 
The evaporation rate of water is fairly low there for keeping the air coming off the towel cool. Place a wet towel in front of/on a box fan or ac unit. You're basically making a radiator.
 
Ah I see. Thanks for the clarification. I just fill up a spray bottle and spray it at the fan occasionally. We have both ceiling fans and an oscillating fan.
 
Another trick is to fill a shallow pan (roaster) with ice and place in front of the fan. I used to do that for my Newfoundland--I'd place box fan on the floor (inside an x-pen so the dogs couldn't knock if over) and place a large tray of ice in front of the fan. It helped before A/C (of course, this was also b/4 TOU electricity rates--I'm back to the tricks I used before A/C to keep cool during the day).
 
The evaporation rate of water is fairly low there for keeping the air coming off the towel cool. Place a wet towel in front of/on a box fan or ac unit. You're basically making a radiator.
Actually you're making an evaporative cooler. It takes heat energy to evaporate water. In other words when water evaporates it sucks up a certain amount of heat, which turns the liquid water into water vapor. Evaporative cooling takes advantage of this, in effect cooling the air in exchange for increasing its humidity.
 
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